Roller pumps



Aug. 18, 1959 Filed Feb. 13, 1957 2 Sheets-Sheet l arm/'5 United States Patent ROLLER PUMPS James J. Becher and Virgil R. Norris, Chicago, 11]., as-

signors to Roll-Flex Industries, Inc., Chicago, 111., a corporation of Illinois Application February 13, 1957, Serial No. 640,039 Claims. (Cl. 103-149) This invention relates to improvements in a sanitary leakproof pump of the type in which the material being pumped is progressively forced through a system of collapsible tubing and more particularly is concerned with pumps of the general class characterized by a casing forming a cylindrical chamber in which a rotatably mounted drive shaft progresses one or more compression 'rollers along an annular path to successively compress and .release the loop of collapsible tubing disposed in the outer regions of the chamber. Thus the rollers force the material to be pumped forwardly through the tubing and set up a suction eifect in their wake.

Prior art pumps of this type have had unduly limited 'efiective lifetimes. The collapsible tubing is subjected to a great amount of wear due to contact with the roller and is also subjected to the intense cyclic compression forces which soon cause it to take a set.

: The short useful lifetime of these pumps has been a drawback on their acceptance and it is the principal object of the present invention to provide an improved pump of this nature that has a greatly extended useful life and that substantially maintains its original capacity.

Another object is to accomplish this broad purpose with an ,efiicient and economical pump construction that offers a substantially uniform load characteristic to its driving motor and'thus permits efiicient matching between the motor and the pump.

Generally speaking, the present invention provides an improved roller pump by utilizing a novel collapsible tubing arrangement. According to the invention the collapsible tubing is extruded or molded in the form of a conventional circular tube that carries a relatively wide inner flange for contact with the pump roller to cushion the action of the roller and absorb the wear imposed by the roller, and a somewhat narrower outer flange that may be gripped between a pair of complementary casing 'members to hold the outer wall of the tube stationary and permit the action of the movable roller to effect an automatic reshaping of the circular tube. Inthe case of the extruded tubing the opposite ends of the inner flange are terminated short of the ends of the tubing and bonded together in abutting relationship to provide a substantially uniform and continous wear surface and also to provide a substantially uniform resistance path for the roller. According to an alternative embodiment, -an'insert is bonded between the shortened ends of the inner flange to bridge the point where the ends of the tubing pass through the pump casing. v

A further feature of the invention resides in the use of a continuous strip of steel or other flexible stretchresisting material which is bonded in the inner flange for hearing the brunt of the reshaping stresses.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same:

Fig. 1 is a front view of the pump with one of the casing members removed;

Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 but illustrates the relaxed condition of the collapsible tubing.

Fig. 4 is a plan sectional view taken on the line 4-4 of Fig. 1;

Fig. 5 is a sectional view through the loop of tubing better illustrating its construction;

Fig. 6 is a detailed side view of the roller arrangement used in the present invention;

Fig. 7 is a fragmentary front view corresponding to Fig. 1 and illustrating the alternative tubing arrangement employing an insert; and

Fig. 8 is a perspective view of the insert.

Referring now to the drawings, and particularly to Fig. 1, the pump casing defines agenerally cylindrical chamber 10 that receives a rotatably mounted drive shaft 11 in driving engagement with a compression roller mechanism 12 that acts upon a length of collapsible tubing 13 formed into a substantially circular loop in the outer regions of the chamber. The pump casing preferably consists of a pair of complementary members 14 and 15 that cooperate to form the chamber and that provide coaxial bearing chambers, 16 and 17 respectively, on opposite sides of the chamber 10. Suitable bearing sleeves 18 are carried in these chambers to support the drive shaft and provide a pump that is extremely quiet in operation. The base 20 for the pump is preferably carried by casing member 15 which is formed with the access opening for the drive shaft 11.

It is preferred to utilize a planetary compression roller arrangement in which the drive shaft directly contacts one or more planetary rollers. Accordingly, an intermediate portion of the drive shaft is formed with a series of serrations 22 extending parallel to the axis of the drive shaft. At the final assembly, spaced apart shoulders 23 are pressed into position on opposite sides of the serrations to center the compression roller mechamsm.

While the invention is useful with a variety of roller arrangements, the use of a pair of rollers 25 on opposite sides of the drive shaft in spaced apart relationship is preferred. The rollers are preferably of nylon or other suitable plastic material and are mounted in the pump in frictional driving contact with the serrations 22. For convenience, the rollers, when originally installed, may be smooth surfaced as the initial operation of the pump permits the shaft to knurl the roller and form an intimately mated driving engagement therebetween. The relative positions of the rollers are maintained by a yoke assembly (Fig. 6) consisting of a pair of centrally apertured plates 26 the ends of which are interconnected by suitable headed fasteners 27 on which the rollers are mounted for free rotation. The roller mounting provides suflicient play to accommodate the desired freedom of movement of each of the rollers.

The present invention solves two important operating problems that have long plagued the roller pump art. First, the collapsible tubing 13 which is acted upon by the compression roller mechanism 12 is subjected to a great amount of wear and has required frequent replacement. In addition, the collapsible pumping tube tends to take a permanent set, causing a decrease in its cross sectional size and causing the pump to operate at a reduced capacity. The present invention solves these problems with a highly simplified and economical construction by employing a novel collapsible tubing arrangement thatis capable of withstanding severe wear and that permits the roller mechanism to perform an automatic reshaping of.

the pumping tube to counteract the tendency of this fii-b' it) take 8 permanent Set.

According to the invention, therefore, the tubing consists of a conventional circular pumping tube 30 that carrres a relatively wide inner flange 31 and a somewhat narrower outer flange 32. The tubing can'be'rriolded-into the" shape "shown, but for cost considerations an extruded tubing arrangement is preferred. When the tubing is Ioo eu'ahout the drive shaft, as shown in Fig. 1, the inner flange 31 extends completely around the inner circumference' of the tubing and the outer flan e 32 extends around a major portion of the outer circumference of therubin It'will be seen that the tubing lies in 'asingle plane within the chamber and its ends are brought through a cofrunon opening in non-overlapping, abutting relationship.

Ais is" apparent from the drawings, the inner and outer flanges both terminate short of the ends of the tubing, and as indicated by the bracketed end portion 41, one end of the inner flange extends beyond the outer flange and is wrapped around into abutting relationship with the eppesite end of the inner flange. The abutting ends are bonded together in any suitable manner to provide a substantially uniform and continuous wear surface for the roller and also to :ofler a substantially uniform resistance path to the roller movement.

In the preferred form of the invention, when the collapsible tubing is extruded with the desired shape shown the drawings, it may be of any suitable resilient and flexible material and is preferably made of a vinyl plastic, though other materials will be more suitable in certain specific applications. 'For example, in high temperature applications silicone would be preferred while neoprene isconsidered most suitable if the material being pumped is ahydrocarbon. Similarly, gum rubber tubing is preferred for food handling or hospital applications.

In an alternative embodiment employing extruded tubing, a separate wear flange segment 42 (see Fig. 8) is inserted between the opposite ends of the integral wear flange 31 to bridge the gap between the ends of the tubing and provide a continuous wear flange. Preferably the insertsegment is heat fused in place and this results in a strong and effective bond capable of withstanding the usual operating forces. The use of the insert 42 with a planar loop of tubing is also particularly eflective in providingsubstantially uniform resistance to the progressive movement of the roller mechanism. In addition it makes most efficient use of the pumping chamber capacity.

In the preferred form, as best shown in Fig. 2, the cooperating casing members are each provided with marginal shoulders 35 that come together in abutting relationship when the pump is assembled. These shoulders are generally circular but extend outwardly at the top of the pump to provide a divided connection boss 36 having a forked passageway 37 that carries the inlet and outlet ends of the pumping tube. The connection boss is arranged to grip the tubing ends snugly so that the hose fittings 43 are secured against slipping or pulling out. The generally circular portions of the shoulders are formed with irregularly shaped internal ledges providing cooperating circumferential surfaces 38 that constitute the outer wall of the chamber 10 and cooperating annular surfaces 39 that grip the integral securing flange $2 to hold the outer wall of the pumping tube substantially stationary. These ledges terminate at the upper ends of the casing members to accommodate a radial opening through the circumferential wall of the pumping chamber and permit the collapsible tubing to be brought out through the forked passageway.

In operation, the rotating drive shaft 11 moves the planetary rollers 25 along an annular path and, as best seen in Fig. 4, the rollers completely collapse the pumping tube and progressively force the material being pumped forwardly through'the tube. As the roller passes, the 2tuber'eturns to its original shape and sets up a suction effect that draws additional material into the pumping chamber.

Generally it is preferred tti use two rollers spaced apart in order to develop the most effective reshaping action. In Fig. 3, the tubing is shown in its relaxed condition within the casing, that is, the condition it assumes in the absence of the roller mechanism. Phantom lines illustrate the rollerlocation and the stressed condition of the tubing'to bring out thefa'ct that the localized compression of the tubing by'therollers places the temporar-ily unen'gaged parts of the tubing in a state of tension due to the fact that the outer wall of the pumping tube is held stationary by the surfaces 39. This tensioning of the collapsible tubing automatically reshapes' it and maintains the pump capacity substantially at its original value.

Because two rollers are employed, there is no possi' bility of losing compression when the gap across the abutting ends of'the tubing is being traversed but in applications that do not call for maintaining continuous compression, obviously one roller may be employed though the tensioning and reshaping action is diminished somewhat. The use of a separate wear flange segment has the advantage thatthis segment may be contoured to best provide a complete and uniform resistance path to 'the'rollers.

The wearflange exhibits a cushioning effect with a. resultant smooth'force application from the rollerto the pumping tube. 'In addition the wear flange is quite rugged and resists wear from the roller. Towards this end, it may be-made of appreciable thickness whereas theeflec- .tiveness of the pumping tube itself would be diminished if its own walls were made unduly rugged.

For optimum p'ump performance, a pumping tube and wear flange having a .good degree of resiliency is important but the cyclic tensioning imposed on the wear flange by the roller reshaping action would ultimately cause the resilient wear flange to elongate with a consequent loss ofthe reshaping action. v It is preferred, therefore, as best shown in Fig. "5, to bond a continuous band 44 of flexiblestretch-resisting material to the face of the inner flange and finally 'a continuous channel-shaped covering strip 45,. preferably 015 the same material as the pumping tube itself, is bonded in place to mask the band 44. The band may-be ofsteel or nylon or any suitable flexible material that is substantially stretch resis'tant under the forcesinvolved. The covering strip 45 is suitably apertured, as at 4i6,to-reduce the surface area of contact with the roller and minimize heat generation.

The securing flange arrangement serves the twofold purpose of anchoring the pumping tube to permit automatic reshaping and of sealing. the chamber. Since the securingflange extends only partially around the chamber 10, it is importantthat the forked passageway create a snug fit with the pumping tube to complete the seal. It isdesirable, from the standpoint of pump .perfornv ance and pump life, to lubricate the pump parts with silicone in which case, the chamber should be adequately sealed.

It should be understood that the description of the preferred form of the invention is for the purpose of complying with section 1-12, title 35 of the United States Code and that the appended claimsshould be construed as broadly as the prior art will permit.

We claim: k

1. In a pump,-a casing defining a cylindrical chamber bounded by an outer circumferential wall, a rotatably mounted drive shaft in said chamber and coaxial therewithycollapsible tubing in said casing surroundingsaid shaft and having its ends extending through said casing, said tubing carrying a wear flange along the major portion of its innercircumference,-with said wear flange having spaced apart opposite ends, a flange insert disposed between the opposite ends of said wear flange to: bridge across the ends of said tubing and provide a substantially uniform continuous wear surface, and compression means 'in driving engagement between said shaft and said wear surface and movable along an annular path in response .to rotation of said shaft to compress successive portions of said tubing against said outer circumferential wall.

2. ha pump, a casing defining a cylindrical chamber bounded by an outer circumferential wall, a rotatably mounted drive shaft in said chamber and coaxial therewith, collapsible tubing in said casing surrounding said shaft and having its ends extending through said casing, the inner wall of said tubing carrying a fixed wear flange forming a substantially uniform continuous wear surface, said flange comprising a portion integral with said tubing and a continuous flexible, stretch-resistant band overlying and bonded to said portion.

-3. In a pump, a casing defining a cylindrical chamber bounded by an outer circumferential wall, a rotatably mounted drive shaft in said chamber and coaxial therewith, collapsible tubing in said casing surrounding said shaft and having its ends extending through said casing, the inner wall of said tubing carrying a fixed wear flange, said flange comprising a portion integral with said tubing, a continuous flexible, stretch-resistant band overlying and bonded to said portion and a covering strip of resilient compressible material bonded in place to overlie said band and provide a continuous wear surface, and compression means in driving engagement between said shaft and said wear surface and movable along an annular path in response to rotation of said shaft to compress successive portions of said tubing against said outer circumferential wall with the portions of the integral wear flange momentarily free from engagement with said compression means being under tensile stress and resisting such stress to relieve the inner wall of said tubing of such stress.

4. In a pump, a casing defining a cylindrical chamber bounded by an outer circumferential wall, a rotatably mounted drive shaft in said chamber and coaxial therewith, collapsible tubing in said casing surrounding said shaft and having its ends extending through said casing, the inner wall of said tubing carrying a fixed wear flange in continuous integral anchoring engagement along the major portion of the inner circumference of said inner wall and forming a substantially uniform continuous wear surface, and compression means in driving engagement between said shaft and said wear surface and movable along an annular path in response to rotation of said shaft to compress successive portions of said tubing against said outer circumferential wall with the portions of the integral wear flange momentarily free from engagement with said compression means being under tensile stress and resisting such stress to relieve the inner wall of said tubing of such stress.

5. In a pump of the type having a casing defining a cylindrical chamber bounded by an outer circumferential wall, a rotatably mounted drive shaft in said chamber and coaxial therewith, collapsible tubing in said chamber surrounding said shaft and having its ends extending through said casing, and roller means in driving engagement between the tubing and shaft and movable along an annular path in response to rotation of said shaft to compress successive portions of said tubing against the outer circumferential wall, the improvement wherein said tubing carries an integral flange along its inner circumference including a portion that bridges across the ends of the tubing to form a substantially continuous circular surface, a continuous flexible, stretchresisting band is bonded to said flange in overlapping relationship, and a covering strip of resilient compressible material is bonded over said band to provide a continuous wear surface for cooperation with the roller means.

6. In a pump, a pair of casing members defining a cylindrical chamber bounded by an outer circumferential Well, said members including cooperating arcuate gripping surfaces outwardly of said wall, a rotatably mounted drive shaft in said chamber and coaxial therewith, a length of collapsible tubing in said chamber surrounding said shaft and having its ends extending through said casing, said tubing carrying a fixed wear flange in continuous engagement around'its inner circumference forming a substantially uniform continuous wear surface and a fixed securing flangein continuous engagement around its outer circumference that is gripped between said arcuate surfaces to hold the outer wall of said tubing stationary, and compression means in driving engagement between said shaft and said wear surface and movable along an annular path in response to rotation of said shaft to compress successive portions of said tubing against said outer circumferential 'wall and simultaneously to tension uncompressed portions of said tubing and automatically reshape the same, with said wear flange resisting tensioning of the tubing to thereby relieve the'tubing of harmful tensioning.

7. In a pump, a pair of casing members defining a cylindrical chamber bounded by an outer circumferential Wall, said members including cooperating arcuate gripping surfaces outwardly of said wall, a rotatably mounted drive shaft in said chamber and coaxial therewith, a length of collapsible tubing in said chamber surrounding said shaft and having its ends extending through said casing, said tubing including an integral securing flange around a major portion of its outer circumference that is gripped between said arcuate surfaces to hold the outer wall of said tubing stationary and a fixed flange around a major portion of its inner circumference, with said fixed flange having spaced apart opposite ends, an insert flange connected between the opposite ends of the fixed flange to bridge across the ends of the tubing and provide a substantially uniform continuous surface, and compression means in driving engagement between said shaft and said surface and movable along an annular path in response to rotation of said shaft to compress successive portions of said tubing against said outer circumferential wall and simultaneously to tension uncompressed portions of said tubing and automatically reshape the same.

8. In a pump of the type having a pair of casing members defining a cylindrical chamber bounded by an outer circumferential wall, a rotatably mounted drive shaft in said chamber and coaxial therewith, collapsible tubing in said chamber surrounding said shaft and having its ends extending out of said chamber, and roller means in driving engagement between the tubing and shaft and movable along an annular path in response to rotation of said shaft to compress successive portions of said tubing against the outer circumferential wall, the improvement wherein said casing members are formed with cooperating arcuate gripping surfaces outwardly of said wall, said tubing carries a fixed securing flange around a major portion of its outer circumference that is gripped between said arcuate surfaces and a fixed wear flange around a major portion of its inner circumference, with said fixed flange having spaced apart oppo site ends, and a separate wear flange connects between the opposite ends of the fixed wear flange to bridge the ends of the tubing and provide a substantially uniform continuous wear surface for cooperation with the roller means.

9. A pumping tube for use in a pump of the type having a casing defining a cylindrical chamber bounded by an outer circumferential wall, a rotatably mounted drive shaft in said chamber and coaxial therewith, collapsible pump tubing in said chamber surrounding said shaft and having its ends extending through said casing, and roller means in driving engagement between the tubing and shaft and movable along an annular path in response to rotation of said shaft to compress sucanemone 7 cessive portions" of said tubing againsttheouter. ci -cum: ferentiaLWall, said tube havingan-rint'egralwear' flange along the major portion of its inner eirenmterenee pro- Vicled with a stretch-resistant band rigidly anchored thereto and said tubing having an integralsecu'ringflan'ge around a major portion of its outer 'eircu'mferenc'e'.

'10. In a pump; a pair of easing nrenrbe'rsdfininga cylindrical chamber bounded -by an outer circumferential wall, said members including cooperating arcuate grippingsurfaces outwardly'of said'wall; a-ro'ta'tably mounted drive shaft in said chamber and coaxial therewith, a lerigt-ll'of collapsible tubing in said'ch'amber surrounding said shaft and 'having its ends extending through said casing, said tubing having an integral wear flange in continuous engagement around its inner circumference and 'a fixed securing flange around its outer circumference that is gripped between said arcuatosurfa'c'es to hold the outer wall of said tubing stationary, a continuous flexible stretch-resistant band fixed in overlying relationship to said integral wear flange; a covering strip fixedly overlyin g: said :band" to provide far submstantiallyuni'z fonn continuous wear surface, and compressiomtmean's in driving engagement between said and said-wear surface l and 'movabl'e along an annular-path in-response to -rotation of said'shaft to compress successive portions of said tubing against said outer circumferential warn and simultaneously to tension uncompressed portiofls' of said tubing and automatically reshape the-same; Y

References Cited inthefile'ofthis patent UNITED STATES PATENTS Great Britain 

